gFTP is a free multithreaded file transfer client for *NIX based machines.
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JFtp is a graphical Java network and file transfer client.
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WinSCP is an open source free SFTP client and FTP client for Windows.
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FireFTP is a free, secure, cross-platform FTP client for Mozilla Firefox which provides easy and intuitive access to FTP servers.
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FileZilla Client is a fast and reliable cross-platform FTP, FTPS and SFTP client with lots of useful features and an intuitive graphical user interface.
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